The absolute altitude change is only 200 vertical feet, but you'll do multiple up-and-down trips, making the total climbing around 800.
Retail Sale is an intermediate-level trail. If you find yourself over your head on Fire Sale, with a few short hike-a-bikes you'll get back to easier riding.

The loop ride starts on Got Milk portion of the Milk and Cookies loop. This trail is also Retail Sale. Head west across the road from the McCoy Corral, and catch the first singletrack on your right. It's a little more technical than the alternate. The two routes join 1/3 mile later.
At mile 1.1, fork hard left at the Fire Sale sign.

Fire Sale undulates back and forth, up and down. At first it tends to follow Retail Sale, coming within 30 feet of Retail Sale near the Milk/Retail fork. Compared to Retail Sale, the trail is narrow and turns tend to be tight.

The trail flirts with the steep sides of two small hills. The trail isn't tough for a rider with good bike control. There aren't any big drops; just a few boulder rollovers. The challenge is narrow trail on steep sideslopes. No room for bobbling.

Fire Sale is a one-way trail, ridden north to south. But if you want to do Fire Sale twice, it's easy to ride Retail Sale back to the Fire Sale fork. (Technically, Retail Sale is also a counterclockwise loop.) Just stay right at all trail intersections as you head back along Retail Sale toward the start of Fire Sale. It's only 1/2 mile. There's one short steep (about 30 feet) that you'll have to push-a-bike up.

Once you rejoin Retail Sale at the south end of Fire Sale, it will be around 6 miles back to the trailhead. Many riders choose to short-circuit the ride at mile 4.2, where a half-mile connector goes back to the trailhead.

Retail Sale slopes gently downhill in the bottom of a southbound wash, then turns northeast and slowly climbs another wash. Once you're at the top of that wash, the trail undulates and twists north for a fun and high-speed return.

Riding notes, Fire Sale:
0.0  Cross paved road to DT  N40 21.019 W109 34.913
       Immediately fork R on ST  N40 21.003 W109 34.928
       Easier route: 100 feet on DT, then fork R
0.3  Trail merges with alternate route  N40 20.992 W109 35.163
1.1  Fork L on Fire Sale (R = Got Milk and Retail Sale) 
       N40 20.830 W109 35.982
3.5  Join Retail Sale, keep L   N40 20.616 W109 35.647
4.2  Fork R (L = quick return)   N40 20.759 W109 35.083
4.3  Fork L (R= Slippery When Wet)  N40 20.679 W109 35.064
7.4  Keep L (Serpendipity joins on R)  N40 20.454 W109 34.418
9.1  R on DT to corral   N40 20.994 W109 34.939
9.2  Back at trailhead

Getting there:
While driving toward Vernal on US-40, pass mile marker 138, then turn right on the narrow paved McCoy Flats road ( N40 23.427 W109 35.752). If you miss McCoy Flats road, go to the viewpoint overlooking Vernal and backtrack exactly 2 miles, then turn left into the road. Drive 3 miles. Immediately after passing a corral on your left, turn into the large fenced BLM trailhead parking lot. 

Camping: BLM land, primitive camping allowed. No developed sites.
Bathroom: At trailhead
Water: Bring your own.
Bike services, maps, trail conditions:
Altitude Cycle, 580 East Main, Vernal. 435-781-2595